1. Field of the Invention
The present invention relates to a contact pin assembly provided for example in a camera body of a single lens reflex camera.
This application is related to the commonly assigned U.S. Pat. No. 4,860,043, the disclosure of which is expressly incorporated by reference herein.
2. Description of Related Art
In a recent single lens reflex camera, there are various functions, such as automatic aperture control, AF (Auto Focus), and PZ (Power Zoom), etc. In such a single lens reflex camera, electrical contact pin assemblies are provided on a camera body and an interchangeable lens. These contact pins of the contact pin assemblies come into contact with each other when the interchangeable lens is attached to the camera body. When in contact, a data communication between the camera body and the interchangeable lens can be carried out, and the interchangeable lens can receive power from the camera body.
It is necessary to bias the contact pins of the electrical contact pin assemblies, on either the camera body or the interchangeable lens, against the contact pins on the other assemblies so as to maintain the necessary pressure for the electrical charges to pass therebetween. Furthermore, the contact pins must be electrically insulated from the associated body mount member or lens mount member, which is made of electrically conductive metal.
To this end, in a known contact pin assembly, the contact pins are slidably fitted into separate insulation annular rings which are provided into the corresponding holes formed in the associated mount members. The contact pins of the camera body, for example, are biased by compression coil springs to project outwardly so as to electrically contact the contact pins of the interchangeable lens.
In the known contact pin assembly, each contact pin must be assembled with a separate insulation ring and a compression coil spring which must then be electrically connected to a predetermined connecting portion of a printed circuit board. This, however, is a complicated assembly.